The paint job on the track is underway.
I am going to suppose the Heybridge Basin Extension was built from mostly new materials, with these sourced locally where possible. There were hardly any other light railways built under the provisions of the 1868 Act of Parliament, so there are no great precedents to follow. Furthermore, the existing line was a profitable operation and brand-new timber was passing along the Navigation every week.
Wagon brakes would be rarely used except when parked, so little brake dust. Haulage was by steam and horse, so there will be oil and maybe ash deposits where locos stood, maybe some some traces of manure, but little more.
I started with foundation coats of grey primer and Camouflage Dark Brown from Halfords. This unified all of the different materials in the model, but the camo paint absorbs most of the light so no detail photos!
Then I painted the details with a few shades of Vallejo acrylics, these applied with a brush and in a very good light. A nice thing about building a smallish diorama is being able to rest the baseboard on its edge to then look down on details like the sides of the rails.
I have tried to represent new rails on new sleepers at the back.
The siding at the front might be secondhand rail on good used sleepers. The highlights on the spike and bolt details aren’t meant to be prototypical, but rather to make the model look better at a usual viewing distance
The hardest parts to paint were the Peco timbers on the Setrack point. I had a few goes because the first attempts to hide the wood grain effect made it stand out even worse. I think this will be okay from a normal viewing distance, but still a bit peculiar in detail photos.
I want the colouring to be lively enough to be interesting but sufficiently subdued to not detract from the trains. This all looks a bit stark to me at the moment, but ballast and weathering should help.
I am especially grateful to
@Rob Pulham, who told me how Vallejo Smoke mixed with a little Silver makes a really good representation of creosote, and to
@Rob R, who told me how a light railway gets its colouring.